A magnetic recording medium comprises a non-magnetic substrate and a metal thin film magnetic layer formed by an oblique evaporating method on the substrate, the non-magnetic substrate being an aromatic polyamide film. The film has a thickness of 3.0 &mgr;m to 6.0 &mgr;m, has a Young's modulus in the transverse direction of 16000 MPa to 18000 MPa, and has a thermal contraction coefficient (in the transverse direction; 180° C. for 30 minutes) of 0.7% to 1.3%. With this structure, it has been found that the thermal deformation (cupping) after the thin film is formed can be prevented to improve head touch and the electromagnetic conversion properties.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A magnetic recording medium comprising: a non-magnetic substrate; a metal thin film magnetic layer formed on the substrate by an oblique vapor evaporating method; a plasma-polymerized carbon layer on the magnetic layer; a lubricant on the carbon layer; and a back coat layer with a thickness of 0.3 m to 0.7 m on a side opposite to the magnetic layer of the substrate, wherein the non-magnetic substrate is an aromatic polyamide film, wherein the film has a Young's modulus in the transverse direction of 16000 MPa to 18000 MPa, and has a thermal contraction coefficient of 0.7% to 1.3%, and wherein the lubricant is represented by R1-A-R2, where R1 is CF 3 (CF 2 ) n , CF 3 (CF 2 ) n (CH 2 ) m , CH 3 (CH 2 ) 1 , or H; A is COOCH(C 1 H 21 1 )CH 2 COO, and R2 is CF 3 (CF 2 ) n , CF 3 (CF 2 ) n (CH 2 ) m , CH 3 (CH 2 ) 1 , or H; provided that R1 noteq R2, n 7 to 17, m 1 to 3, and l 7 to 30.
2. A magnetic recording medium according to claim 1 , wherein the non-magnetic substrate has a thickness of 3.0 m to 6.0 m.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
March 29, 2002
April 27, 2004
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